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1.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802928

RESUMO

Blood platelets' adenosine receptors (AR) are considered to be a new target for the anti-platelet therapy. This idea is based on in vitro studies which show that signaling mediated by these receptors leads to a decreased platelet response to activating stimuli. In vivo evidence for the antithrombotic activity of AR agonists published to date were limited, however, to the usage of relatively high doses given in bolus. The present study was aimed at verifying if these substances used in lower doses in combination with inhibitors of P2Y12 could serve as components of dual anti-platelet therapy. We have found that a selective A2A agonist 2-hexynyl-5'-N-ethylcarboxamidoadenosine (HE-NECA) improved the anti-thrombotic properties of either cangrelor or prasugrel in the model of ferric chloride-induced experimental thrombosis in mice. Importantly, HE-NECA was effective not only when applied in bolus as other AR agonists in the up-to-date published studies, but also when given chronically. In vitro thrombus formation under flow conditions revealed that HE-NECA enhanced the ability of P2Y12 inhibitors to decrease fibrinogen content in thrombi, possibly resulting in their lower stability. Adenosine receptor agonists possess a certain hypotensive effect and an ability to increase the blood-brain barrier permeability. Therefore, the effects of anti-thrombotic doses of HE-NECA on blood pressure and the blood-brain barrier permeability in mice were tested. HE-NECA applied in bolus caused a significant hypotension in mice, but the effect was much lower when the substance was given in doses corresponding to that obtained by chronic administration. At the same time, no significant effect of HE-NECA was observed on the blood-brain barrier. We conclude that chronic administration of the A2A agonist can be considered a potential component of a dual antithrombotic therapy. However, due to the hypotensive effect of the substances, dosage and administration must be elaborated to minimize the side-effects. The total number of animals used in the experiments was 146.


Assuntos
Monofosfato de Adenosina/análogos & derivados , Adenosina-5'-(N-etilcarboxamida)/análogos & derivados , Antitrombinas/farmacologia , Fibrinogênio/metabolismo , Cloridrato de Prasugrel/farmacologia , Agonistas do Receptor Purinérgico P1/farmacologia , Trombose/metabolismo , Monofosfato de Adenosina/farmacologia , Adenosina-5'-(N-etilcarboxamida)/farmacologia , Adulto , Animais , Pressão Sanguínea/efeitos dos fármacos , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Cloretos , Diástole/efeitos dos fármacos , Feminino , Compostos Férricos , Humanos , Fluxometria por Laser-Doppler , Masculino , Camundongos Endogâmicos C57BL , Permeabilidade/efeitos dos fármacos , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Sístole/efeitos dos fármacos
2.
Artigo em Inglês | MEDLINE | ID: mdl-33801904

RESUMO

Chlorine is a critical element with respect to the use of fossil fuel, recycling of industrial wastes, and water purification. Chlorine could form toxic chemical compounds, corrode pipe systems and boilers, and contaminate surface and ground waters. Calcium aluminate-layered double hydroxides are one of the most promising materials to remove chlorides due to the chemisorption mechanism, since the phases have positively charged interlayers. Many studies on the synthesis and the characterization of calcium aluminate-layered double hydroxides have been extensively conducted, whereas few studies have been conducted on the chloride removal characteristics of the phases. The state-of-the-art studies on the synthesis methods and the structural characteristics of CaAl-LDH phases, the underlying mechanism on the removal of chlorides, and the potential removal rate and the capacity in the present study were thoroughly reviewed.


Assuntos
Cloretos , Poluentes Químicos da Água , Adsorção , Compostos de Alumínio , Compostos de Cálcio , Cloro , Hidróxidos
3.
J Wound Care ; 30(4): 284-296, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33856907

RESUMO

BACKGROUND: Traditionally, infections are treated with antimicrobials (for example, antibiotics, antiseptics, etc), but antimicrobial resistance (AMR) has become one of the most serious health threats of the 21st century (before the emergence of COVID-19). Wounds can be a source of infection by allowing unconstrained entry of microorganisms into the body, including antimicrobial-resistant bacteria. The development of new antimicrobials (particularly antibiotics) is not keeping pace with the evolution of resistant microorganisms and novel ways of addressing this problem are urgently required. One such initiative has been the development of antimicrobial stewardship (AMS) programmes, which educate healthcare workers, and control the prescribing and targeting of antimicrobials to reduce the likelihood of AMR. Of great importance has been the European Wound Management Association (EWMA) in supporting AMS by providing practical recommendations for optimising antimicrobial therapy for the treatment of wound infection. The use of wound dressings that use a physical sequestration and retention approach rather than antimicrobial agents to reduce bacterial burden offers a novel approach that supports AMS. Bacterial-binding by dressings and their physical removal, rather than active killing, minimises their damage and hence prevents the release of damaging endotoxins. AIM: Our objective is to highlight AMS for the promotion of the judicious use of antimicrobials and to investigate how dialkylcarbamoyl chloride (DACC)-coated dressings can support AMS goals. METHOD: MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify published articles describing data relating to AMS, and the use of a variety of wound dressings in the prevention and/or treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent and/or treat wound infection in a manner that does not kill or damage the microorganisms (for example, by actively binding and removing intact microorganisms from wounds) were then narratively reviewed. RESULTS: The evidence reviewed here demonstrates that using bacterial-binding wound dressings that act in a physical manner (for example, DACC-coated dressings) as an alternative approach to preventing and/or treating infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS. CONCLUSION: Some wound dressings work via a mechanism that promotes the binding and physical uptake, sequestration and removal of intact microorganisms from the wound bed (for example, a wound dressing that uses DACC technology to successfully prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS (for example, reducing the use of antimicrobials in wound treatment regimens) by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.


Assuntos
Anti-Infecciosos/administração & dosagem , Gestão de Antimicrobianos/métodos , Bandagens , Cloretos/administração & dosagem , Infecção da Ferida Cirúrgica/prevenção & controle , Ferimentos e Lesões/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Resistência Microbiana a Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
4.
J Water Health ; 19(2): 288-305, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33901025

RESUMO

Water from underground intakes is the main source of potable water for people in Poland, hence the protection of its resources is of great importance for the functioning of society and the economy. A new regulation in Polish Water Law imposes the obligation of performing risk analysis for water intakes, including the assessment of health hazards, factors negatively affecting water quality which are identified on the basis of hydrogeological and geological analyses. The main objective of the study was to determine the health risk for chlorides and to present an innovative approach to the health risk for non-toxic substances. In Upper Silesia, which is the most industrialized and urbanized area in Poland, old mining shafts are often used as deep wells in the water supply chain, and higher mineralization is the key feature of abstracted water which does not quite eliminate them as a source of drinking water supply. This paper proposes a new method of health risk determination as hazard index (HI). We present analysis of the health risks with increased concentration of chlorides in water which cause health effects for water consumers, especially for men, children aged 4-8, pregnant women and women during lactation.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Criança , Pré-Escolar , Cloretos , Monitoramento Ambiental , Feminino , Humanos , Masculino , Polônia , Gravidez , Medição de Risco , Poluentes Químicos da Água/análise , Abastecimento de Água
5.
Environ Sci Technol ; 55(8): 5382-5392, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33733765

RESUMO

This study is the first to demonstrate the capability of Cl- to markedly accelerate organic oxidation using thermally activated peroxymonosulfate (PMS) under acidic conditions. The treatment efficiency gain allowed heat-activated PMS to surpass heat-activated peroxydisulfate (PDS). During thermal PMS activation at excess Cl-, accelerated oxidation of 4-chlorophenol (susceptible to oxidation by hypochlorous acid (HOCl)) was observed along with significant degradation of benzoic acid and ClO3- occurrence, which involved oxidants with low substrate specificity. This indicated that heat facilitated HOCl formation via nucleophilic Cl- addition to PMS and enabled free chlorine conversion into less selective oxidizing radicals. HOCl acted as a key intermediate in the major oxidant transition based on temperature-dependent variation in HOCl concentration profiles, kinetically retarded organic oxidation upon NH4+ addition, and enabled rapid organic oxidation in heated PMS/HOCl mixtures. Chlorine atom that formed via the one-electron oxidation of Cl- by the sulfate radical served as the primary oxidant and was involved in hydroxyl radical production. This was corroborated by the quenching effects of alcohols and bicarbonates, reactivity toward multiple organics, and electron paramagnetic resonance spectral features. PMS outperformed PDS in degrading benzoic acid during thermal activation operated in reverse osmosis concentrate, which was in conflict with the well-established superiority of heat-activated PDS.


Assuntos
Cloretos , Poluentes Químicos da Água , Cloro , Temperatura Alta , Oxirredução , Peróxidos , Poluentes Químicos da Água/análise
6.
Int J Mol Sci ; 22(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33673022

RESUMO

Grain legumes are important crops, but they are salt sensitive. This research dissected the responses of four (sub)tropical grain legumes to ionic components (Na+ and/or Cl-) of salt stress. Soybean, mungbean, cowpea, and common bean were subjected to NaCl, Na+ salts (without Cl-), Cl- salts (without Na+), and a "high cation" negative control for 57 days. Growth, leaf gas exchange, and tissue ion concentrations were assessed at different growing stages. For soybean, NaCl and Na+ salts impaired seed dry mass (30% of control), more so than Cl- salts (60% of control). All treatments impaired mungbean growth, with NaCl and Cl- salt treatments affecting seed dry mass the most (2% of control). For cowpea, NaCl had the greatest adverse impact on seed dry mass (20% of control), while Na+ salts and Cl- salts had similar intermediate effects (~45% of control). For common bean, NaCl had the greatest adverse effect on seed dry mass (4% of control), while Na+ salts and Cl- salts impaired seed dry mass to a lesser extent (~45% of control). NaCl and Na+ salts (without Cl-) affected the photosynthesis (Pn) of soybean more than Cl- salts (without Na+) (50% of control), while the reverse was true for mungbean. Na+ salts (without Cl-), Cl- salts (without Na+), and NaCl had similar adverse effects on Pn of cowpea and common bean (~70% of control). In conclusion, salt sensitivity is predominantly determined by Na+ toxicity in soybean, Cl- toxicity in mungbean, and both Na+ and Cl- toxicity in cowpea and common bean.


Assuntos
Cloretos/toxicidade , Phaseolus/efeitos dos fármacos , Cloreto de Sódio/toxicidade , Sódio/toxicidade , Soja/efeitos dos fármacos , Vigna/efeitos dos fármacos , Biomassa , Phaseolus/crescimento & desenvolvimento , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Tolerância ao Sal/efeitos dos fármacos , Soja/crescimento & desenvolvimento , Especificidade da Espécie , Vigna/classificação , Vigna/crescimento & desenvolvimento
7.
Molecules ; 26(4)2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33673047

RESUMO

The analysis of stability of biologically active compounds requires an accurate determination of their structure. We have found that 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles are generally unstable in the presence of acids and bases and are rearranged into the salts of spiropyrazolinium compounds. Hence, there is a significant probability that it is the rearranged products that should be attributed to biological activity and not the primarily screened 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles. A series of the 2-amino-8-oxa-1,5-diazaspiro[4.5]dec-1-en-5-ium (spiropyrazoline) benzoates and chloride was synthesized by Boulton-Katritzky rearrangement of 5-substituted phenyl-3-[2-(morpholin-1-yl)ethyl]-1,2,4-oxadiazoles and characterized using FT-IR and NMR spectroscopy and X-ray diffraction. Spiropyrazolylammonium chloride demonstrates in vitro antitubercular activity on DS (drug-sensitive) and MDR (multidrug-resistant) of MTB (M. tuberculosis) strains (1 and 2 µg/mL, accordingly) equal to the activity of the basic antitubercular drug rifampicin; spiropyrazoline benzoates exhibit an average antitubercular activity of 10-100 µg/mL on MTB strains. Molecular docking studies revealed a series of M. tuberculosis receptors with the energies of ligand-receptor complexes (-35.8--42.8 kcal/mol) close to the value of intermolecular pairwise interactions of the same cation in the crystal of spiropyrazolylammonium chloride (-35.3 kcal/mol). However, only in complex with transcriptional repressor EthR2, both stereoisomers of the cation realize similar intermolecular interactions.


Assuntos
Antituberculosos/química , Benzoatos/química , Oxidiazóis/química , Tuberculose/tratamento farmacológico , Antituberculosos/farmacologia , Benzoatos/farmacologia , Cloretos/química , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Oxidiazóis/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo , Relação Estrutura-Atividade , Tuberculose/microbiologia
8.
Am J Physiol Lung Cell Mol Physiol ; 320(5): L845-L879, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33655758

RESUMO

Airway submucosal gland serous cells are important sites of fluid secretion in conducting airways. Serous cells also express the cystic fibrosis (CF) transmembrane conductance regulator (CFTR). Protease-activated receptor 2 (PAR-2) is a G protein-coupled receptor that activates secretion from intact airway glands. We tested if and how human nasal serous cells secrete fluid in response to PAR-2 stimulation using Ca2+ imaging and simultaneous differential interference contrast imaging to track isosmotic cell shrinking and swelling reflecting activation of solute efflux and influx pathways, respectively. During stimulation of PAR-2, serous cells exhibited dose-dependent increases in intracellular Ca2+. At stimulation levels >EC50 for Ca2+, serous cells simultaneously shrank ∼20% over ∼90 s due to KCl efflux reflecting Ca2+-activated Cl- channel (CaCC, likely TMEM16A)-dependent secretion. At lower levels of PAR-2 stimulation (

Assuntos
Cloretos/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Glândulas Exócrinas/patologia , Infecções por Pseudomonas/microbiologia , Receptor PAR-2/metabolismo , Mucosa Respiratória/patologia , Membrana Serosa/patologia , Cálcio/metabolismo , Células Cultivadas , AMP Cíclico/metabolismo , Glândulas Exócrinas/metabolismo , Glândulas Exócrinas/microbiologia , Humanos , Pseudomonas aeruginosa/isolamento & purificação , Mucosa Respiratória/metabolismo , Mucosa Respiratória/microbiologia , Membrana Serosa/metabolismo , Membrana Serosa/microbiologia
9.
Am J Physiol Renal Physiol ; 320(5): F719-F733, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33719576

RESUMO

Phosphorylation of the thiazide-sensitive NaCl cotransporter (NCC) in the distal convoluted tubule (DCT) is altered rapidly in response to changes in extracellular K+ concentration ([K+]). High extracellular [K+] is believed to activate specific phosphatases to dephosphorylate NCC, thereby reducing its activity. This process is defective in the human disease familial hyperkalemic hypertension, in which extracellular [K+] fails to dephosphorylate NCC, suggesting an interplay between NCC-activating and NCC-inactivating switches. Here, we explored the role of STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) and intracellular Cl- concentration in the rapid effects of extracellular K+ on NCC phosphorylation. SPAK was found to be rapidly dephosphorylated in vitro in human embryonic kidney cells and ex vivo in kidney slices by high [K+]. Acute high-K+ challenge resulted in DCT1-specific SPAK dephosphorylation in vivo and dissolution of SPAK puncta. In line with the postulate of interplay between activating and inactivating switches, we found that the "on" switch, represented by with no lysine kinase 4 (WNK4)-SPAK, must be turned off for rapid NCC dephosphorylation by high [K+]. Longer-term WNK-SPAK-mediated stimulation, however, altered the sensitivity of the system, as it attenuated rapid NCC dephosphorylation due to acute K+ loading. Although blockade of protein phosphatase (PP)1 increased NCC phosphorylation at baseline, neither PP1 nor PP3, singly or in combination, was essential for NCC dephosphorylation. Overall, our data suggest that NCC phosphorylation is regulated by a dynamic equilibrium between activating kinases and inactivating phosphatases, with kinase inactivation playing a key role in the rapid NCC dephosphorylation by high extracellular K+.NEW & NOTEWORTHY Although a great deal is known about mechanisms by which thiazide-sensitive NaCl cotransporter is phosphorylated and activated, much less is known about dephosphorylation. Here, we show that rapid dephosphorylation by high K+ depends on the Cl- sensitivity of with no lysine kinase 4 and the rapid dephosphorylation of STE20/SPS1-related proline-alanine-rich protein kinase, primarily along the early distal convoluted tubule.


Assuntos
Cloretos/metabolismo , Túbulos Renais Distais/enzimologia , Potássio na Dieta/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Células HEK293 , Humanos , Cinética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Transporte Proteico , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Membro 3 da Família 12 de Carreador de Soluto/metabolismo
10.
Water Res ; 195: 116973, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33677242

RESUMO

Though hydroxylamine (NH2OH) is effective for accelerating pollutants degradation in Fenton and Fenton-like systems, the effect of anions simultaneously introduced by the hydroxylamine salts have always been ignored. Herein, effect of two commonly used hydroxylamine salts, hydroxylamine hydrochloride (NH2OH·HCl) and hydroxylamine sulfate [(NH2OH)2·H2SO4], for the degradation of dimethyl phthalate (DMP) in peroxymonosulfate (PMS)/Fe(II) system was comparatively investigated. Degradation efficiency of DMP with NH2OH·HCl was 1.6 times of that with same dosages of (NH2OH)2·H2SO4. SO4·-, Fe(IV) and ·OH formed in the PMS/Fe(II)/NH2OH system, but ·OH was the major species for DMP degradation. Addition of Cl- significantly improved the production of ·OH and Cl·, and the exposure dose of ·OH (CT·OH) was more than 10 times that of CTCl· as the concentration of Cl- increased to 1 mM. Calculations based on branching ratios of Cl· and ·OH indicated that the reactions of Cl- with SO4·- and Cl· with H2O were not the only production sources of ·OH in the system. Further experiments with methyl phenyl sulfoxide (PMSO) as the probe indicated that Cl- would facilitate the shift of reactive species from Fe(IV) to radicals (SO4·- or ·OH) in the system. Both hydroxylation and nitration intermediate products were detected in the oxidation of DMP. Cl- promoted the formation of hydroxylation intermediates and reduced the formation of nitration intermediates. This study revealed for the first time that Cl- could shift reactive species from Fe(IV) to radicals in PMS/Fe(II) system, raising attention to the influence of the coexisting anions (especially Cl-) for pollutants oxidation in iron-related oxidation processes.


Assuntos
Cloretos , Peróxidos , Compostos Ferrosos , Ferro , Oxirredução
11.
Sci Total Environ ; 775: 145867, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-33621870

RESUMO

Natural conversion of metal species is an important source for nanoscale metal particles in the aquatic environment, and it could affect their fate and toxicity. Extracellular polymeric substances (EPSs) are ubiquitous and abundant in the aquatic environment, thus likely can reduce metal ions to nanoscale particles. However, the effect of natural inorganic ligand and light on this process has not been well investigated. In this work, Ag+ was readily reduced to silver nanoparticles (AgNPs, around 15 nm in size) by the EPS collected from Chlorella pyrenoidosa. AgNPs could be generated in the dark environment but at a slow rate. Visible light accelerated the photoreduction. The reaction mechanism probed by Fourier transform infrared spectroscopy and three-dimensional excitation-emission matrix spectrometry demonstrated that the reduction in Ag+ was attributed to the protein and polysaccharides in the EPS. The presence of chloride ions (Cl-) largely shortened the duration of photoreduction. Scanning electron microscopy results indicated that with the aid of EPS, the AgCl nanocrystal was converted to core-shell structure, with dot-like nano Ag acting as the shell and the AgCl nanocrystal acting as the core. Size and morphological changes were observed on transmission electron microscopy. This study adds new knowledge of the joint effect of light exposure, Cl-, and EPS on the formation of AgNPs from Ag+ and advances the understanding of the natural formation mechanism of AgNPs.


Assuntos
Chlorella , Nanopartículas Metálicas , Cloretos , Matriz Extracelular de Substâncias Poliméricas , Íons , Prata
13.
Ecotoxicol Environ Saf ; 212: 111968, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33550083

RESUMO

Despite the fact that copper (Cu) is a vital micronutrient to maintain body function, high doses of Cu through environmental exposure damage various organs, especially the liver, which is the main metabolic organ. To investigate the influence of long-term Cu-induced toxicity on mitophagy and apoptosis in rat liver, 96 seven-month-old male Sprague-Dawley rats were fed TBCC for 24 weeks. The results revealed that exposure to high Cu concentrations could promote oxidative stress liver injury by increasing the hepatic function index (ALT, AST and ALP) and MDA content, while reducing the activity of antioxidant enzymes (T-SOD, GSH-Px and CAT) related to oxidative stress. Consistent with histopathological observations, proper dietary Cu (15-60 mg/kg) could improve antioxidant stress levels and induce a dose-dependent increase in the mRNA expression of mitophagy-related genes, whereas a high Cu concentration (120 mg/kg) could cause severe liver impairment and ultrastructural changes and a reduction in mitophagosomes, accompanied by downregulation of Atg5, Beclin1, Pink1, Parkin, NIX, P62 and LC3B. The expression of apoptosis-related genes (Bax, Bax/Bcl-2, Caspase3, Cytc and p53) and proteins (Caspase3 and p53) was upregulated with the addition of dietary Cu. The results demonstrated that an appropriate dose of TBCC could improve liver function by promoting mitophagy and Cu enzymes that play antioxidative roles, while the accumulation of excess Cu could induce liver lesions by enhancing apoptosis and inhibiting mitophagy pathways.


Assuntos
Cloretos/toxicidade , Cobre/toxicidade , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Sulfato de Cobre/análise , Dieta , Fígado/metabolismo , Masculino , Mitofagia/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Testes de Toxicidade Crônica
14.
Bull Environ Contam Toxicol ; 106(4): 647-651, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33564929

RESUMO

In this study, glutathione reductase (GR) from baker's yeast (Saccharomyces cerevisiae) was exposed to 0, 25, 50, 100, 250 and 500 mg/L copper(II) oxide nanoparticles (CuO NPs) and copper(II) chloride (CuCl2). Changes in GR% activity upon exposure to 25, 50, 100, 250 and 500 mg/L CuO NPs and CuCl2 were found to be + 0.3, - 3.4, - 8.1, - 25.7 and - 37.4 and - 60.7, - 72.7, - 77.8, - 85.3 and - 90.6, respectively. The 50% inhibition concentration (IC50) was 625 ppm (78.6 × 10-4 M) for CuO NPs and 21 ppm (1.56 × 10-4 M) for CuCl2. Moreover, CuO NPs and CuCl2 inhibited GR competitively and noncompetitively, respectively.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Cloretos , Cobre/toxicidade , Glutationa Redutase , Nanopartículas Metálicas/toxicidade , Óxidos , Saccharomyces cerevisiae
15.
Waste Manag ; 123: 60-68, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33561771

RESUMO

Non-metallic components (NMC) in waste printed circuit boards (WPCBs) are made of the thermosetting epoxy resin and glass fiber, which has been a research concern in the waste recycling area. The recycling of thermosetting epoxy resin is a serious challenge due to their permanent cross-linked structure. An efficient approach to chemical recycling of epoxy resin for resource reutilization was developed in this research. ZnCl2/CH3COOH aqueous solution was selected as catalysts system to decompose epoxy resin under a mild reaction condition. The influence of reaction parameters such as reaction temperature, time, liquid-solid ratio and ZnCl2 amount on the decomposition efficiency of epoxy resin and reaction mechanism were investigated. The physical and chemical properties of NMC, reaction solvent and decomposed products were analyzed using scanning electron microscope(SEM), Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectrometry (GC-MS). Results showed that up to 81.85% of epoxy resin could be dissolved by using a temperature of 190 °C during 8 h with a mixture of acetic acid (15 wt%): ZnCl2 (5 g) 20 mL/g. Incompletely coordinated zinc ions enables the cleavage of CN, CBr and CO bonds in the thermosetting brominated epoxy resin, which was mainly converted to phenol, 2-Bromophenol and 2, 4-Dibromophenol with high resource value. And the functional groups of ethyl acetate and acetic acid maintained chemical structure before and after reaction. This research provided a practical approach to the dissolution and reutilization of NMC in WPCBs.


Assuntos
Cloretos , Resíduo Eletrônico , Pós , Reciclagem , Solubilidade , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Nat Commun ; 12(1): 785, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542223

RESUMO

The binding of cytoplasmic Ca2+ to the anion-selective channel TMEM16A triggers a conformational change around its binding site that is coupled to the release of a gate at the constricted neck of an hourglass-shaped pore. By combining mutagenesis, electrophysiology, and cryo-electron microscopy, we identified three hydrophobic residues at the intracellular entrance of the neck as constituents of this gate. Mutation of each of these residues increases the potency of Ca2+ and results in pronounced basal activity. The structure of an activating mutant shows a conformational change of an α-helix that contributes to Ca2+ binding as a likely cause for the basal activity. Although not in physical contact, the three residues are functionally coupled to collectively contribute to the stabilization of the gate in the closed conformation of the pore, thus explaining the low open probability of the channel in the absence of Ca2+.


Assuntos
Anoctamina-1/metabolismo , Cálcio/metabolismo , Ativação do Canal Iônico , Proteínas de Neoplasias/metabolismo , Anoctamina-1/genética , Anoctamina-1/ultraestrutura , Sítios de Ligação/genética , Cátions Bivalentes/metabolismo , Cloretos/metabolismo , Microscopia Crioeletrônica , Células HEK293 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Mutagênese , Mutação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/ultraestrutura , Ligação Proteica , Conformação Proteica em alfa-Hélice
17.
Nat Commun ; 12(1): 786, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542228

RESUMO

The anion channel TMEM16A is activated by intracellular Ca2+ in a highly cooperative process. By combining electrophysiology and autocorrelation analysis, we investigated the mechanism of channel activation and the concurrent rearrangement of the gate in the narrow part of the pore. Features in the fluctuation characteristics of steady-state current indicate the sampling of intermediate conformations that are successively occupied during gating. The initial step is related to conformational changes induced by Ca2+ binding, which is ensued by rearrangements that open the pore. Mutations in the gate shift the equilibrium of transitions in a manner consistent with a progressive destabilization of this region during pore opening. We come up with a mechanism of channel activation where the binding of Ca2+ induces conformational changes in the protein that, in a sequential manner, propagate from the binding site and couple to the gate in the narrow pore to allow ion permeation.


Assuntos
Anoctamina-1/metabolismo , Cálcio/metabolismo , Ativação do Canal Iônico , Modelos Moleculares , Proteínas de Neoplasias/metabolismo , Regulação Alostérica , Anoctamina-1/genética , Anoctamina-1/ultraestrutura , Sítios de Ligação/genética , Cátions Bivalentes/metabolismo , Cloretos/metabolismo , Células HEK293 , Humanos , Cinética , Método de Monte Carlo , Mutação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/ultraestrutura , Técnicas de Patch-Clamp , Distribuição de Poisson , Ligação Proteica/genética , Conformação Proteica em alfa-Hélice
18.
Environ Sci Pollut Res Int ; 28(7): 7691-7709, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33400105

RESUMO

Chlorine (Cl) in the terrestrial environment is of interest from multiple perspectives, including the use of chloride as a tracer for water flow and contaminant transport, organochlorine pollutants, Cl cycling, radioactive waste (radioecology; 36Cl is of large concern) and plant science (Cl as essential element for living plants). During the past decades, there has been a rapid development towards improved understanding of the terrestrial Cl cycle. There is a ubiquitous and extensive natural chlorination of organic matter in terrestrial ecosystems where naturally formed chlorinated organic compounds (Clorg) in soil frequently exceed the abundance of chloride. Chloride dominates import and export from terrestrial ecosystems while soil Clorg and biomass Cl can dominate the standing stock Cl. This has important implications for Cl transport, as chloride will enter the Cl pools resulting in prolonged residence times. Clearly, these pools must be considered separately in future monitoring programs addressing Cl cycling. Moreover, there are indications that (1) large amounts of Cl can accumulate in biomass, in some cases representing the main Cl pool; (2) emissions of volatile organic chlorines could be a significant export pathway of Cl and (3) that there is a production of Clorg in tissues of, e.g. plants and animals and that Cl can accumulate as, e.g. chlorinated fatty acids in organisms. Yet, data focusing on ecosystem perspectives and combined spatiotemporal variability regarding various Cl pools are still scarce, and the processes and ecological roles of the extensive biological Cl cycling are still poorly understood.


Assuntos
Cloro , Ecossistema , Cloretos/análise , Cloro/análise , Halogenação , Solo
19.
Adv Exp Med Biol ; 1293: 55-71, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33398807

RESUMO

Cl--pump rhodopsin is the second discovered microbial rhodopsin. Although its physiological role has not been fully clarified, its functional mechanism has been studied as a model for anion transporters. After the success of neural activation by channel rhodopsin, the first Cl--pump halorhodopsin (HR) had become widely used as a neural silencer. The emergence of artificial and natural anion channel rhodopsins lowered the importance of HRs. However, the longer absorption maxima of approximately 585-600 nm for HRs are still advantageous for applications in mammalian brains and collaborations with neural activators possessing shorter absorption maxima. In this chapter, the variation and functional mechanisms of Cl- pumps are summarized. After the discovery of HR, Cl--pump rhodopsins were confined to only extremely halophilic haloarchaea. However, after 2014, two Cl--pump groups were newly discovered in marine and terrestrial bacteria. These Cl- pumps are phylogenetically distinct from HRs and have unique characteristics. In particular, the most recently identified Cl- pump has close similarity with the H+ pump bacteriorhodopsin and was converted into the H+ pump by a single amino acid replacement.


Assuntos
Cloretos/metabolismo , Bombas de Próton/metabolismo , Prótons , Rodopsinas Microbianas/metabolismo , Animais , Bacteriorodopsinas/metabolismo , Halorrodopsinas/metabolismo , Luz , Bombas de Próton/química , Bombas de Próton/efeitos da radiação , Rodopsinas Microbianas/química , Rodopsinas Microbianas/efeitos da radiação
20.
Environ Sci Technol ; 55(4): 2575-2584, 2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33497196

RESUMO

Aromatic polyamide-based membranes are widely used for reverse osmosis (RO) and nanofiltration (NF) treatment but degrade when exposed to free chlorine (HOCl/OCl-). The reaction mechanisms with free chlorine were previously explored, but less is known about the role of bromide (Br-) in these processes. Br- may impact these reactions by reacting with HOCl to form HOBr, which then triggers other brominating agents (Br2O, Br2, BrOCl, and BrCl) to form. This study examined the reactivities of these brominating agents with a polyamide monomer model compound, benzanilide (BA), and a modified version of it, N-CH3-BA. The results indicated that all these brominating agents only attacked the aromatic ring adjacent to the amide N, rather than the amide N, different from the previously examined chlorinating agents (HOCl, OCl-, and Cl2) that attacked both sites. Orton rearrangement was not observed. Species-specific rate constants (ki, M-1 s-1) between BA and HOBr, Br2O, Br2, BrOCl, and BrCl were determined to be (5.3 ± 1.2) × 10-2, (1.2 ± 0.4) × 101, (3.7 ± 0.2) × 102, (2.2 ± 0.6) × 104, and (6.6 ± 0.9) × 104 M-1 s-1, respectively, such that kBrCl > kBrOCl > kBr2 > kBr2O > kHOBr. N-CH3-BA exhibited lower reactivity than BA. Model predictions of BA loss during chlorination with varied Br- and/or Cl- concentrations were established. These findings will ultimately enable membrane degradation and performance loss following chlorination in mixed halide solutions to be better predicted during pilot- and full-scale NF and RO treatment.


Assuntos
Cloro , Purificação da Água , Brometos , Cloretos , Cinética , Nylons
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